PINS chemical identification software

Abstract

An apparatus and method for identifying a chemical compound. A neutron source delivers neutrons into the chemical compound. The nuclei of chemical elements constituting the chemical compound emit gamma rays upon interaction with the neutrons. The gamma rays are characteristic of the chemical elements constituting the chemical compound. A spectrum of the gamma rays is generated having a detection count and an energy scale. The energy scale is calibrated by comparing peaks in the spectrum to energies of pre-selected chemical elements in the spectrum. A least-squares fit completes the calibration. The chemical elements constituting the chemical compound can be readily determined, which then allows for identification of the chemical compound.

What is claimed is:  
     
       1. A method for identifying a chemical substance, the method comprising: 
       exposing said chemical substance to neutrons from an isotopic neutron source;  
       measuring, with a high purity germanium detector, gamma rays emitted by said chemical substance as a result of exposure to said neutrons;  
       creating a single spectrum of between 4096 and 16384 channels and a detection count per spectrum channel, said detection count corresponding to the number of detected gamma rays;  
       calibrating from said single spectrum, an energy scale based on energies within said single spectrum of neutron-induced gamma rays generated from said detector, shielding materials or container materials;  
       performing a peak-by-peak analysis of the corresponding gamma-ray energies of chemical elements of interest on said spectrum; and  
       identifying said chemical substance based on said peak-by-peak analysis of said single spectrum.  
     
     
       2. The method of  claim 1  further comprising displaying chemical elements comprising said identified chemical substance. 
     
     
       3. The method of  claim 2  further comprising displaying a confidence level associated with the identified chemical elements. 
     
     
       4. The method of  claim 1  further comprising displaying the identified chemical substance. 
     
     
       5. The method of  claim 1  further comprising displaying a confidence level associated with the identified chemical substance. 
     
     
       6. The method of  claim 1  wherein the step of identifying the chemical substance comprises determining a presence, if any, of a first chemical element selected from the group of phosphorous and chlorine, and a ratio of second elements selected from the group consisting of arsenic, boron, hydrogen, nitrogen, oxygen, phosphorous, sulfur, silicon, titanium and zinc. 
     
     
       7. The method of  claim 1  further comprising a step of calibrating an electronic gain of said high purity detector to adjust a known gamma-ray peak to a pre-selected channel of said high purity detector. 
     
     
       8. The method of  claim 7  wherein said known gamma-ray peak is associated with hydrogen. 
     
     
       9. The method of  claim 8  wherein said known gamma-ray peak associated with hydrogen is generated from neutron interactions within a hydrogenous moderator block. 
     
     
       10. The method of  claim 9  wherein the moderator block comprises polyethylene. 
     
     
       11. A method for identifying a chemical substance, the method comprising: 
       inducing neutrons from an isotopic neutron source into a chemical substance, said neutrons interacting within the chemical substance to generate characteristic gamma-rays;  
       measuring, with a high purity germanium detector, energies of said gamma-rays to create a single gamma-ray energy spectrum;  
       calibrating from said single spectrum, an energy scale based upon energies within said single spectrum of neutron-induced gamma rays generated from said detector, shielding materials or container materials;  
       performing a directed peak fit analysis comprising determining peak centroids and net peak areas extracted from said calibrated, single spectrum to determine gamma-ray counting rates for chemical elements of interest;  
       identifying chemical elements and their ratios contained in said chemical substance;  
       identifying said chemical substance by determining a presence, if any, of a first clement and at least one second element.  
     
     
       12. The method of  claim 11  wherein said first element concentration is selected from the group consisting of phosphorous and chlorine. 
     
     
       13. The method of  claim 11  wherein said at least one second element concentration is selected from the group consisting of arsenic, boron, hydrogen, nitrogen, oxygen, phosphorous, sulfur, silicon, titanium and zinc. 
     
     
       14. The method of  claim 11  further comprising the step of calibrating an electronic gain of said high purity detector to adjust a known gamma-ray peak to a pre-selected channel of said high purity detector. 
     
     
       15. The method of  claim 14  wherein said known gamma-ray peak is associated with hydrogen. 
     
     
       16. The method of  claim 15  wherein said known gamma-ray peak associated with hydrogen is generated from neutron interactions within a hydrogenous moderator block. 
     
     
       17. The method of  claim 16  wherein the moderator block comprises polyethylene. 
     
     
       18. The method of  claim 11  wherein data file information of at least one known chemical element and gamma-ray peaks associated therewith is selected from the group consisting of iron and chlorine. 
     
     
       19. The method of  claim 11  wherein data information of known chemical elements and gamma-ray peaks associated therewith is comprised of elements contained within said detector, shielding materials or container materials. 
     
     
       20. The method of  claim 19  wherein said data information of known chemical elements is selected from the group consisting of germanium, bismuth, aluminum, and iron. 
     
     
       21. The method of  claim 11  further comprising displaying the identified chemical elements. 
     
     
       22. The method of  claim 11  further comprising displaying the identified chemical substance. 
     
     
       23. The method of  claim 11  further comprising displaying a confidence level associated with the identified chemical elements. 
     
     
       24. The method of  claim 11  further comprising displaying a confidence level associated with the identified chemical substance.